I seem to have gotten everything working. The plots show a 280 kHz Murata ceramic filter with an 82 pF load on its output. The dB and group delay curves are similar to those published by Murata for a 230 kHz filter.
I spent a lot of time looking for bugs when I noticed that S12 > 1 for some capacitive loads. I finally found two references that explained how this was possible for a passive device for a complex port reference impedance. It does not indicate a violation of conservation of energy as it would for a real reference impedance. I am using pseudo-wave analysis instead of the older power-wave analysis. They yield identical results for real reference impedances, but only pseudo-wave can handle complex impedances.
I'm going to spend some time checking for bugs as I changed a lot of code. I'll post a message when the new version is available.
Brian
